Unraveling “whodunit” mysteries when cattle or big game animals are killed by predators can be a gory, gooey business, but there’s vital clues in the carcasses for those who know how to look.
And regarding which predator made the kill — wolf, mountain lion or grizzly bear — sometimes the answer is, none of them.
All predators are also scavengers, and frequently, a predator came along and started munching on an animal that was already dead from some other cause.
Predatory Kills Can Get Messy
It can be easy for the untrained eye to mistake a deer carcass scavenged by wolves for one that wolves have killed, according to biologists of the Voyageurs Wolf Project.
They study wolf behavior in and around Voyageurs National Park, Minnesota.
At kill sites, the deer remains will often be scattered, and wolves will frequently dismember their prey and carry off the limbs, according to the wolf project.
Wolves tend to be neater about scavenging, sometimes just pulling out organs to feast on, according to researchers.
Wolf Caches
It’s much the same with wolves in the West, Robert Crabtree, who is founder, chief scientist and president of the Yellowstone Ecological Research Center, told Cowboy State Daily.
Wolves in parts of Yellowstone National Park have been eating fewer elk and more bison, he said.
Healthy adult bison are generally too tough and dangerous for wolves to drag down. However, the park’s bison population is so high, there are more old and weak animals that die naturally. So wolves will go out scavenging bison carcasses, he said.
When wolves pack off carcass parts, it’s usually for one of two reasons, Crabtree said.
They’re either trying to “cache” the meat, or hide it from other predators, he said. Or they’re taking it back to the den to feed their pups, he said.
When wolves and other wild canines, coyotes and foxes, cache meat in the warmer months, they’ll cover it with dry vegetation, he said.
“The funny thing is, they’ll tamp the cover down with their noses,” Crabtree said.
That’s because if they used their paws, it might leave their scent and give the location away, he said.
‘Grape Jelly’
During his long career as a federal trapper, Carter Niemeyer of Idaho investigated countless suspected predator kills, mostly on livestock.
Just looking at external damage to a carcass won’t tell an investigator whether an animal was actually killed by predators, he said.
Dead giveaways for an attack include crushed flesh from bite wounds, as well as blood clots and bruising under the skin, he said.
“It’s essential that you skin them (carcasses) out” for an investigation, he said.
“Look for blood clots that look like jelly. Between the crushed flesh, the grape jelly and the bruising, you have evidence that the animal was alive when a predator attacked it,” he said.
Wolves bite so hard, damage under the skin can look like “gunshot wounds,” he said.
“With beef cattle, the wolves’ teeth don’t really puncture all the way through the hide. They just crush the flesh underneath and leave bruising, kind of like if you got your hand caught in a vice,” he said.
Crabtree agreed that bruising or blood clots under the skin usually mean an animal was killed by predators.
“If you can get to the site soon enough and skin the carcass out, there’s always red and bruising under the skin,” he said. “That means there was still blood pressure during the attack, so the prey bled out underneath the skin.”
This elk was probably already long dead when a mountain lion scavenged the carcass, according to evidence at the scene. (Courtesy Dan Thompson/Wyoming Game and Fish Department) 
Unraveling “whodunit” mysteries when cattle or big game animals are killed by predators can be a gory, gooey business, but there’s vital clues in the carcasses for those who know how to look. (Courtesy Photo)
Which Predator Did It?
The location and types of wounds can also help determine which predator made the kill.
Bears usually launch a blitz attack, leaving ghastly wounds on the “neck, shoulder and back areas,” of the carcass, Niemeyer said.
Mountain lions are more meticulous. They might try to suffocate a prey animal by latching onto its neck and crushing the windpipe, Niemeyer said.
Or they might try to bite through the neck at the base of the skull.
Bite marks down an animal’s hindquarters and flanks indicate a wolf pack attack, Niemeyer said.
Where mountain lions prefer ambush attacks, wolves with chase their prey and drag it down, he said.
Helps Determine Compensation
Being able to tell predator kills from scavenging is important for managing conflicts between predators and ranchers, Wyoming Game and Fish Large Carnivore Specialist Dan Thompson told Cowboy State Daily.
“We use this regularly as part of evaluations when a producer has a dead calf, and we also use this as part of studies to look at diet composition of carnivores. We see scavenging with all these species, especially with bears, due to their life history patterns, but just because a bear is eating on a dead elk or domestic calf doesn't mean it killed it,” Thompson said.
“Everything is more nuanced in the real world, but this knowledge and decades of experience, expertise and prior results allow us to scientifically and consistently evaluate these dynamics, such as livestock depredation and fair compensation for damage,” he added.
During one investigation of an elk carcass, it was determined that a mountain lion had eaten some of the elk, but not until long after the elk was dead, he said.
There was “no hemorrhaging in the neck or vertebral area below cranium indicative of a lion kill,” he said.
‘Meat Drunk’
Regardless of the state of a carcass, the wolves feasting on it always have competition in Yellowstone, Crabtree said.
Wolves can gorge themselves into a stupor, he said.
“Us biologists call it ‘meat drunk.’ The wolves get 15-20 pounds of meat in their bellies and then the wander off,” he said.
Then coyotes, ravens, eagles and other opportunists will move in.
“When then wolves come back to the carcass, that’s when they’ll kill coyotes,” Crabtree said.
Over the years, wolves in Yellowstone have taken to hunting at night, he added, although researchers aren’t quite sure why.
It might because the wolves got weary of crowd of tourists gathering to gawk at them when they were hunting or packing meat back to their pups at in their dens, he said.
Stopped cars seem to bother wolves much more than traffic that is moving, he added.
“We’re not sure why they’re killing more at night. Perhaps to avoid disturbances,” Crabtree said.
Mark Heinz can be reached at mark@cowboystatedaily.com.
